This is a segment of the mutant intestine (3.5 day old fish, lateral view of the intestine) in a transgenic mutant zebrafish that expressed the green fluorescent protein tagged to a peptide that binds to actin in epithelial cells. Invasive cells with protrusions expand out in to the surrounding tissue stroma (arrows). The green structure on the top of the movie frame is the kidney duct. The intestine is below the kidney duct. The actin-rich protrusions are the invadopodia.